问题 解答题
解方程.
2
7
+x=
11
21

x-
5
12
=
7
24

x+
1
4
=1-
1
4
答案

(1)

2
7
+x=
11
21

2
7
+x-
2
7
=
11
21
-
2
7

x=

5
21

(2)x-

5
12
=
7
24

x-

5
12
+
5
12
=
7
24
+
5
12

x=

17
24

(3)x+

1
4
=1-
1
4

x+

1
4
=
3
4

x+

1
4
-
1
4
=
3
4
-
1
4

x=

1
2

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